Abstract

An explicit, time-domain, finite-element method is shown to calculate the reverberation time in realistic acoustic spaces using desktop computing resources. The reverberation time is defined as the time required for reflections of direct sound to decay 60 dB, and is also the principal quantity in architectural acoustics across the frequency ranges of interest. Current industry practice for calculating the reverberation time involves empirically derived formulae which cannot account for the architectural complexity of modern acoustic spaces or the detailed placement of acoustic treatments. Computing advances over the past several years have made it possible to calculate the reverberation time using finite element models in the time domain. Explicit finite-element codes are distinct from traditional ones because they operate by integrating the governing equations of mass, momentum, and energy in the time domain, avoiding the need for matrix generation, storage, and factorization. The feasibility of this full-wave approach is demonstrated using the configurations of real example acoustic spaces. Comparison is made with empirical calculations and experimental measurements. It is also shown how the enhancements can be made to a space by the addition of acoustic damping material.